Grate.



C. B. ROBERTS.

Gam.

APPLICATION FILED APR. 6. I9I4.

Patented May 11, 1915.

4 SHEETS-SHEET lA THU u uhmw- Witnesses lh f C' B- ROBERTS.

GRATE.

APPLICATION FILED APR. 6. I9I4.

Patented May11, 1915 4 SHEETS-SHEET 2.

I f mrt .La-IF Mefzjw' www@ fw C. B. ROBERTS.

GRATE.

APPLlc/mon mso Ara. s. 1914.

1,138,976. Patented May11,1915.

4 SHEETS-SHEET 3.

Saas" THE NORRIS PETERS CO.. PHomLlrHo.. WASHINGmN. DA C.

C. B. ROBERTS.

GRATE.

Patented May 11, 1915.

4 SHEETS-SHEET 4.

000 0 000 0 00 00 00 00 0 000 0 H0H0Av0H0H OAV CLAUDE B. ROBERTS, OF BELFAST, MAINE.

iGrRA'rE.

Specification of Letters Patent.

Patented May 11, 1915.

Application led April 6, 1914. Serial No. 829,916.

T0 all whom t may concern.'

Be it known that I, CLAUDE B. ROBERTS, a citizen of the United States, residing at Belfast, in the county of Waldo and State of Maine, have invented an Improvement in Grates, of which the following is a specification.

This invention relates to improvements in furnace grates constructed with a view to obtaining a very high eiiiciency and rating for a long period of time, as contrasted with a short period of time which has heretofore been obtained, the grate being especially designed for burning small sized soft coal with a natural draft.

One of the objects of the invention is the construction of the grate-bars to provide for maximum air distribution as compared with their area; another object is the construction of the grate-bars and their relative disposition whereby they may be moved forward and backward from a middle position for the purpose of shaking, and when so moved will pass beneath and will raise those portions of the fuel-bed with which they are in contact slightly and moderately, and sufficiently to enable the ash to be separated from the active fuel, said grate-bars, when in all said positions, being disposed entirely beneath the fuel-bed, as contrasted to projecting into the fuel-bed more or less when moved forward and backward and thereby over-agitating the same and forming holes or pockets therein and subjecting the projecting portions to 'the action of the intense heat with a consequent liability of burning out the grate-bars, and necessitating frequent renewals; another object is the construction of oscillating grate-bars arranged for movement forward and backward from a middle position, whereby the maximum openings produced between said bars when so moved will not be greater than the openings through the bars, although said bars have a movement several times greater than the width or size of said openings; another object of the invention is the construction of the grate-bars arranged for movement forward and backward from a middle position for shaking purposes, as aforesaid, and also having a greater movement in one direction only, as forward for instance, for dumping purposes, and when moved into dumping position the areas of the openings between the grate-bars will be very substantially and quickly increased;

another object is the provision of stationary grate-bars at the ends of the grate, arranged in parallel relation with the grate-bars, which are constructed and arranged to admit of movement of the grate-bars forward and backward from a middle position for shaking purposes, yet the maximum areas of the openings produced between said stationary bars and the grate-bars will not exceed the areas of the openings through the grate-bars except when said grate-bars are moved into dumping position, at which time the areas of said openings are very substantially and quickly increased; another object is the provision of sharp or well defined edges on the grate-bars and also on their supports which aid in breaking up clinkers which pass through the openings in or be tween the grate-bars; another object is the arrangement of the grate-bars in grate-forming relation, whereby separate sets are provided, each section comprising a plurality of grate-bars, and a stationary grate-bar is arranged between the sets, in parallel relation therewith, the construction of the gratebars against said stationary grate-bars differing from the remaining grate-bars, so that when oscillated they may be moved forwaid and backward from a middle position and the maximum areas of the openings thereby produced between said stationary grate-bar and the movable grate-bars will not exceed the areas of the openings through the grate-bars, except when the grate-bars are moved into dumping position; another object is the provision of means arranged on my improved form of grate-bar which admits of detachable connection with a barcarrier, so that when disabled it may be replaced by a new grate-bar.

Figure 1 is a plan view of a furnace-grate embodying this invention, many of the gratebars being omitted. Fig. 2 is a transverse vertical section of the grate taken on the dotted line 2 2, Fig. 1. Fig. 3 is an enlarged longitudinal vertical section of the grate taken on the dotted line 3 3, Fig. l, showing the bar-carriers broken away to save space. Fig. 4 is an enlarged detail view of several grate-bars at one end of the grate, a bar-carrier therefor and operatingmeans, said grate-bars being moved forward into dumping position. Fig. 5 is a similar view, the grate-bars being moved forward from a middle position in the act of shaking. Fig. 6 is a similar detail view of several grate-bars arranged adjacent a stationary grate-bar, they being represented in their extreme forward positions in the act of shaking. Fig. 7 is an enlarged top plan View of one of the grate-bars. Fig. 8 is a bottom plan View, and Fig. 9 is a side elevation, and Fig. 10 is an end elevation of the same.

The improved grate-bar of which, of course, there are a plurality, constituting the grate, consists of a metallic section 1, curved transversely in the arc of a circle from edge to edge and of rectangular outline, in plan, (see Figs. 7 to 10). Said section is formed with a series of openings 2, arranged in rows, which rows are arranged diagonally with respect to the side edges of the section, and each of said openings is of diamondshape in plan, having their major dimensions arranged directly transverse the bar. The openings extend wholly through the section and their lower dimensions or the side of the openings at the bottom or lower side of the section exceeds the same dimensions at the upper or fuel side of the section, so that the walls of the openings are downwardly divergent from top to bottom. These openings are so formed that their medial lines from top to bottom are arranged in parallel relation or substantially so, instead of being radial, thus affording a direct downward passage for the ash, permitting the ash to fall by gravity without obstruction. These openings are shaped and arranged relative to each other as described, with a View to providing the maximum etliciency in air admission and distribution without sacrificing strength, the idea being to economize fuel instead of material in the construction of the grate-bar. and the taper which is given to them not only allows for the free and unobstructed passage of the ash but also affords a greater area of air to pass through the bottom than would ordinarily pass through the top, so that the air is caused to pass through the top with an increased velocity in order that it will gradually fish-tail through the fuel-bed, thereby insuring more complete combustion. Both the side and end edges of the section 1, are formed with parti-openings 3, corresponding in shape and size to the other openings, so that when the bars are arranged in grateforming relation. although slightly spaced apart to provide for expansion, the portion of the openings of adjacent bars will register to form complete openings.

At appropriate points on the grate-bars the openings are omitted and the lower surfaces of the bar at such imperforate portion is formed with depending lugs 4, each lug having a vertical slot 5 extending upward from its extremity for a portion of its length to receive the bar-carriers on which the grate-bars are detachably arranged. In view of the fact that the openings are arranged in rows diagonally with respect to the edges of the section the imperforate portions thereof from which the lugs depend are diagonally' arranged and the lugs are likewise diagonally arranged, but the slots in said lugs are arranged in parallel relation with the side-edges of the section to receive the bar-carriers which are arranged in parallel relation with the sideedges of the section. two such lugs arranged near the ends thereof to support it upon the bar-carrier. The lower extremities of the end-edges of the section 1, as 6, and also the side-edges of the lugs are formed with sharp or well deined edges to serve as cutting-edges to break up or crush any clinkers which may pass between the bars during the shaking operation.

The mounting of the grate-bars within the fire-box in grate-forming relation includes longitudinal stringers such as eye-beams 7, extended from front to rear of the fire-box and arranged in parallel relation, two or more such beams being employed, according to the width of the grate, there being spaces between each pair of beams, and a plurality of bar-carriers 8 are arranged transversely across said spaces and are remo ably supported at their endsA in bearing-boxes arranged on said beams, said bar-carriers each consisting of a thin fiat quadrilateral bar, having journals 9 at its ends. which journals rest in the bearing-boxes, the thickness of said bars corresponding to the width of the slots 5 in the lugs on the grate-bars, so that the grate-bars may repose on said bar-carrier and permit of ready removal therefrom and application thereto. As here shown each bar-carrier has mounted upon it four grate-bars which are arranged in alinement, but a greater or lesser number may be arranged thereon. Said bar-carriers are arranged in parallel relation throughout the length of each space between the beams 7, and are properly spaced apart to support the grate-bars free from contact with each other and with small additional spaces betwen said grate-bars to provide for expansion. Said bar-carriers rigidly support the grate-bars and when oscillated in their endbearings cause said grate-bars to move forward and backward from a middle position. Said grate-bars normally occupy a middle position, see Fig. 2, and when so disposed relative to each other they present an undulatory surface for the fuel-bed on account of their transversely curved sections. The barcarriers and the sections 1 of the grate-bars are so proportioned that the distance from the fulcrum of the bar-carriers to the tops of the grate-bars is less than the radius of the arc of the section l as for instance, the arc of the section 1 of the grate-bar is arranged on a six inch radius and the distance As here shown each grate-bar has betwen the fulcrum of the bar-carriers and the top of the section 1 is tive inches. These relative proportions are of importance, as when the grate-bars are oscillated during the shaking operation and are moved forward and backward from the middle position the sections 1 will raise the fuel-bed gently yet sufiiciently to cause separation of the ash from the active fuel but not enough to over-agitate the fuel, and to produce holes or pockets therein. Such a slight lifting of those portions of the fuel-bed with which the grate-bars come in contact is of importance, and the structure here shown by which this result may be accomplished is very simple, adding nothing to the cost of manufacture.

lVhen arranging the grate-bars in grateforming relation the spaces between the grate-bars are narrow, being of less or at least of no greater width than the width of the openings through the grate-bars, and when said grate-bars are oscillated and caused to move forward and backward from a middle position for shaking purposes these narrow openings will not be substantially increased in area, notwithstanding it will be noted that the movement of the sections 1 of the grate-bars is several times greater than the width of said openings. In one embodiment of my invention the maximum openings produced between the grate-bars are approximately of an inch, being about the same as the openings through the grate-bars, while the travel of said grate-bars is about 2112- inches under the fuel-bed. Thus during the shaking operation the grate-bars slide or move along the bottom of the fuel-bed forward and backward a considerable distance and also lift the fuel-bed slightly which results in gently separating the ash from the active fuel and causing it to fall through the grate without over-agitating the fuel-bed, and such result will be accomplished notwithstanding the oscillations of the gratebars may be produced in rapid succession. Also at each end of the space between the beams 7 a stationary grate-bar 13 is arranged having a grate-section at the top with downwardly extended lugs 14, which lugs enter sockets formed in bars 15, which rest on the beams 7, and which are arranged in parallel relation with the oscillating barcarriers. The tops of the stationary endbars 13 are or may be arranged slightly above the tops of the oscillating grate-bars, although they may be arranged on a level; and their edges adjacent the grate-bars are beveled on their under sides, permitting the adjacent grate-bars to extend beneath said beveled edges when in their middle positions, see Fig. 2, and to move beneath them when moved forward and backward from a middle position during the shaking operation, so as not to produce openings between them of a width greater than the Width of the openings through the grate-bars.

To oscillate the bar-carriers and thereby rock the grate-bars in the manner heretofore described, each bar-carrier has a downwardly extended arm 2O near one end or at any other suitable place, all the arms of a set of bar-carriers being arranged in alinement and a bar 21 is arranged for loose connection with said arms by pins 22. Said bar 21 extends through a hole in the front wall of the furnace and is arranged for engagement with an operating-lever. As here shown, the forwardly projecting end of said bar 21 has a notch 23 to receive a pin 24 extended laterally from an operating-lever Q5 which is pivotally supported at 26 and arranged for detachable connection with its pivot and which is guided in its forward movements by a slotted extension 27 having a small plate 28 pivotally arranged thereon for limiting the movement of said operating-lever in one direction. By moving said operating-lever forward and backward the several bar-carriers of the set and the gratebars connected with them are correspondingly moved for shaking purposes, and by swinging the plate 28 out of the path of movement of said operating-lever said lever may be further moved in an outward direction, thereby to further move the bar-carriers and grate-bars borne by them into dumping position, see Fig. 4, in which position it will be observed that the openings between the grate-bars rapidly increase in area as said bars are moved.

When arranging the grate-bars in grateforming relation, as here shown, and the grate is of large area, the spaces between the beams 7 are made quite long and arranged for two sets of grate-bars which are mounted on a plurality of bar-carriers, as for instance, there may be six bar-carriers in each set, having grate-bars arranged thereon. Between said sets a stationary bar-carrier 10 is arranged on the beam 7, having arranged upon it and in alinement thereon several grate-bars 12, which are stationary on account of the bar-carrier on which they are arranged being stationary, although they are formed with transversely curved gratesections and have depending lugs like the aforesaid grate-bars. In order to provide for arranging the rows of grate-bars adjacent said intermediate stationary gratebar 12, so as to admit of movement thereof forward and backward from a middle position without substantially increasing the area of the openings between them, the side edges of the grate-sections 12 are beveled on their under sides, as at 40, see Fig. 6, preferably in the arc of a circle, to admit of movement of the adjacent side edges of the grate-sections of the adjacent gratebars, and the grate-sections of said adjacent rows of grate-bars have their edges adjacent the edges of the stationary grate sections 12 arranged to move beneath the beveled edges of said sections 12; and the opposite edges of said grate-sections are beveled, as at 45, to admit of the edges of the next row of' grate-bars to be moved beneath them.

In orderl to provide against the production of openings of too large an area between the stationary grate-sections and the adjacent grate-bars and also between said adjacent grate-bars and the next row of grate-bars when the grate-bars are oscillated, the oscillating movement of said adjacent row of grate-bars is reduced, as compared with the oscillating movement of the remaining grate-bars. To accomplish this result the bar-carriers of the rows of gratebars next said intermediate stationary gratesections are connected by short links 4G, with the depending lugs on the bar-carriers of the next row at points more or less remote from their extremities, thereby reducing the leverage and the extent of movement, and at the same time enabling said adjacent gratebars to be oscillated with the other gratebars of the set with which they are associated and by the same operating-means. In case there are two or more sets of gratebars, as before desribed, the bar-carriers of the second or rearmost set are or may be connected together by a connecting-bar 50, and the grate-bar adjacent the intermediate stationary grate-bar may be connected by a link 51 with the arm on the adjacent barcarrier and a bracket may be arranged on said connecting-bar :J0 to which a long bar 53 is connected.,l which bar extends iorward through a hole in the front wall and is or may be connected with said operatinglever Q5 in the manner heretofore described in connection with the bar Q1.

I claim i- 1. An oscillating grate-bar consisting of a transversely curved section having openings through it from top to bottom and having parti-openings at the side and end, and having the lower extremity of the side-edges formed coincident with the extremity of the wall of the adjacent opening to form cutting edges, substantially as described.

2. Ain oscillating grate-bar consisting of a transversely curved section having openings through it from top to bottom and having lugs arranged beneath and extended downward from it for engagement with bar-carriers, the side-edges of said lugs bcing made sharp to form cutting edges, substantially as described.

3. A grate comprising two sets of oscillating bar-carriers arranged in parallel relation and grate-bars arranged thereon havingl transversely curved grate-sections, a stationary grate-bar arranged between said sets of oscillating grate-bars, means for connecting together the bar-carriers of each set, said connecting means involving a connection with the bar-carriers adjacent said intermedate stationary grate-bar whereby said adjacent bar-carriers are caused to move through shorter arcs than the remaining bar-carriers, substantially as described.

i. A grate comprising two sets of oscillating bar-carriers arranged in parallel relation and grate-bars arranged thereon having transversely curved grate-sections, a row of stationary grate-bars arranged between said sets ot oscillating grate-bars having their edges beveled on their under sides and the adjacent grate-sections being arranged to provide for movement of the next rows ot grate-sections without substantially increasing the areas ot the openings produced upon oscillations thereof, means for connecting together the bar-carriers ot each set, said connecting-means involving a connection with the bar-carriers adjacent said stationary grate-bars, whereby said adjacent bar-carriers are caused to move through shorter arcs than the remaining bar-carriers of the sets, substantially as described.

5. A grate including a stationary grate bar, a plurality of sets ot oscillating grate bars arranged on opposite sides orn the stationary grate bar, grate bar rocking means, and connections between said rocking means and the respective sets ot grate bars. said connections being adjusted to rock the set of grate bars adjacent the stationary grate liar through a shorter arc than the grate bars ot the remaining set.

6. grate including` a stationary grate bar, a plurality ot sets of oscillating grate bars arranged on opposite sides ot the stationary grate bar, grate bar rocking means, and connections between said rocking means and the respective sets of grate bars adjusted to rock the set of grate bars adjacent the stationary grate bar through a shorter arc than the remaining grate bars, said grate bars being each formed with a plurality of regularly arranged uniform openings, and sifid rocking means being normally limited in in' vement to prevent separation of proximate edges of adjacent grate bars in excess of the width of the openings in said bars.

In testin'ionv whereof, I have signed my name to this speciiication, in the presence of two subscribing witnesses.

CLAUDE B. ROBERTS.

I'Vitnesses:

H. N. CARGILL, II. C. DRowN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

